In an existing wireless communication system, a Remote User Equipment (Remote UE), such as a wearable device, may transmit data through a Relay User Equipment (Relay UE), such as an existing common mobile phone user equipment. As shown in FIG. 1, a Relay UE may help a Remote UE to complete data transmission. As shown in FIG. 2A and FIG. 2B, a Relay UE and a Remote UE may establish a control plane connection through the same base station or different base stations, while the Relay UE helps the Remote UE to complete data forwarding. At this time, if the Relay UE or the Remote UE moves, the base station(s) will be required to carry out handover to ensure continuity of data transmission.
However, in practical applications, a Relay UE and a Remote UE are likely to be in the same location, e.g. both on a user. At this time, both the Relay UE and the Remote UE are likely to move in the same direction and at the same speed at the same time. If cell handover is required in the moving process, currently, a base station usually hands over the two UEs separately. As such, if the two UEs are handed over to cells covered by different base stations, relay transmission between the Relay UE and the Remote UE will be greatly affected.